If you go for SLA battery, get AGM instead of gel.
AGM is better for deep cycle and better for constant charging and discharging.
Get 10Ah AGM batteries for the most reasonable range, price.
Since these batteries are heavy, you better find a local store who sell them instead of having them shipped.
Also, spend some money to purchase a good charger. It extends your battery life.
Sigh......
AGM is Absorbed Glass Matt.
They are NO WHERE NEAR AS ABLE TO PUT OUT HIGH CURRENTS AS SLA.
Full stop!
THEY SUCK FOR HIGH DISCHARGE. PERIOD!
My '450w' currie ezip has a 35A pwm (factory)
A set of 10Ah 12v x 2 to get 24v Sealed Lead Acid can't put out more than
about 18A, if I used AGM I doubdt I would get 5A
Understand that a "10Ah battery" is 10 amps across TWENTY HOURS. Ie:1/2amp for 20hrs. Any higher discharge and capacity is nearly logrythmically <sp> reduced.
High current discharge spanks lead acid badly.
Single 10Ah pack on my bike = 5.8miles
Ran two in parallel and got 19mi and saw major increase in torque since it
then could put out the full 35A on hills..
Of course at that point I had a 94lb bike......hrrm
It's now LiFEp04 40ah@24v, single 18.8lb pack vs two at 16lbs each.
I geto an honest 45+miles even in Pittsburgh Hills and the math based on
my 9.5-10A at full throttle on the flat is that it can do 15-17mph for four hours!
AGM are NOT for HIGH DISCHARGE like an ebike. These people selling them
as direct replacement for SLA are WRONG / FRAUD / SALESMEN
Do some more research, you'll see what I mean.
While we're on the subject of Lead Acid and chargers...
Anything more than one tenth of capacity for charge (called 1/10C) is agressive. Most ebike chargers are around 1.8Amps into a 10Ah pack..
Expect about
THREE HUNDRED RECHARGES before the pack is nearly shot.
(60% range)
LiFEp04 is rated at 80% at TWO THOUSAND recharges, they really are the best deal in town when you consider replacement costs.